The accuracy of the numerical solution for soil temperature may be tested if boundary conditions and homogeneous soil properties are chosen (see switch Analytical Solution). In such a case an additional auxiliary temperature for each layer may be calculated to test the numerical solution of soil temperatures using the same analytical solution equation as for the lower boundary temperature above, eq. (1.13). Note that this exact temperature calculation assumes the boundary conditions of a sinus variation and can not be estimated from the energy balance (“Surface Temperature”) or for a non frozen soil.